Certified GKH Gardening Expert
No, they cannot. It sounds like you have a mislabled plant or a fused fruit. There are varieties of tomatoes called stuffers that can look very similar to peppers, they are even hollow inside like peppers (and good for stuffing, hence the name stuffers).
There is also a condition where two or more blossoms fuse together and the fruit essentially grows as a siamese twin fruit. This can also give the tomato a pepper like shape.